Port Listening

I'm not sure what you call it but I think there's some type of software port listeners or analyzers, but it describes each port connected or in use and what's using it whether it's a program or an ip address, need some type of software like this, googled and came up with nothing.

SysInternals has a great variety of freeware. Among them:


http://www.sysinternals.com/Utilities/Portmon.html